Contactors are used to electrically test integrated circuit chips. Typically, a chip is loaded in a test chuck and the contactor makes electrical contact with the chip. A load board is electrically connected to the contactor and provides signals to the contactor and processes signals from the contactor.
U.S. patents and Published Patent Applications Nos. U.S. Pat. No. 7,042,240; 2005/0189957; 2006/0164,111; 2006/0145718; and U.S. Pat. No. 6,626,682, all incorporated herein by this reference, disclose various integrated circuit (IC) testing devices.
Sometimes, individual ICs are tested on an assembly strip before being singulated into single ICs. An IC strip is positioned in a test chuck handler. The test chuck handler includes one or more heaters for heating the IC strip. The test chuck handler also includes one or more temperature sensors for monitoring the temperature of the test chuck. A contactor contacts the IC strip and electrically tests the individual ICs thereof.
If the handler is not set up correctly, the strip, for example, a golden reference strip, does not sit correctly on the test chuck during calibration. If a golden strip is not seated correctly, the temperature calibration errors calculated are incorrect. Devices subsequently tested may then be trimmed to incorrect values. And, if the strip being tested is not seated correctly, the ICs thereof are trimmed to incorrect values.
Sometimes, the integrated circuit chip being tested has a temperature sensor built into the integrated circuit. The integrated circuit maybe heated to various temperatures by the test chuck and the temperature sensor in the integrated circuit is adjusted (trimmed) during the test to read the correct value. If the integrated circuit is not correctly positioned in the test chuck, it is not heated properly to the correct value and the result will be that the integrated circuit is trimmed to the wrong value or values. Also, even if the integrated circuit is positioned correctly in the test chuck, its actual temperature (and the temperature of the integrated circuit) may not be known to a sufficient precise value.